Local and systemic N signaling are involved in Medicago truncatula preference for the most efficient Sinorhizobium symbiotic partners
Article first published online: 2 MAY 2012
© 2012 INRA. New Phytologist © 2012 New Phytologist Trust
Volume 195, Issue 2, pages 437–449, July 2012
How to Cite
Laguerre, G., Heulin-Gotty, K., Brunel, B., Klonowska, A., Le Quéré, A., Tillard, P., Prin, Y., Cleyet-Marel, J.-C. and Lepetit, M. (2012), Local and systemic N signaling are involved in Medicago truncatula preference for the most efficient Sinorhizobium symbiotic partners. New Phytologist, 195: 437–449. doi: 10.1111/j.1469-8137.2012.04159.x
- Issue published online: 15 JUN 2012
- Article first published online: 2 MAY 2012
- Received: 5 December 2011, Accepted: 21 March 2012
- adaptative response;
- Medicago truncatula;
- nitrogen fixation;
- nodule development;
- partner choice;
- systemic N signaling
- •Responses of the Medicago truncatula–Sinorhizobium interaction to variation in N2-fixation of the bacterial partner were investigated.
- •Split-root systems were used to discriminate between local responses, at the site of interaction with bacteria, and systemic responses related to the whole plant N status.
- •The lack of N acquisition by a half-root system nodulated with a nonfixing rhizobium triggers a compensatory response enabling the other half-root system nodulated with N2-fixing partners to compensate the local N limitation. This response is mediated by a stimulation of nodule development (number and size) and involves a systemic signaling mechanism related to the plant N demand. In roots co-infected with poorly and highly efficient strains, partner choice for nodule formation was not modulated by the plant N status. However, the plant N demand induced preferential expansion of nodules formed with the most efficient partners when the symbiotic organs were functional. The response of nodule expansion was associated with the stimulation of symbiotic plant cell multiplication and of bacteroid differentiation.
- •A general model where local and systemic N signaling mechanisms modulate interactions between Medicago truncatula and its Sinorhizobium partners is proposed.